A conventional sliding window generally includes a sliding window and a fixed window. The sliding window includes a locking device which is engaged with a cooperated device on the fixed window. The user has to completely pull the sliding window down to a close position and then the user has to operate the locking device to lock the window. The user could forget to lock the window after the sliding window is completely pulled down and this could result in a dangerous break-in crime.
The present invention intends to provide a latch device that automatically locks the windows after the sliding window is completely pulled down. The latch device includes a handle for rotating a driving member which has an eccentric mechanism for moving the latch member to be engaged with a cooperated frame on a fixed part of the window.